Plot

The episode begins with Sonic running through the Great Unknown until he stops at the edge of a steep drop. Suddenly, a portal to the Void opens up in front of him and begins to suck him in. After struggling to outrun the suction effect, Sonic pulls a Power Ring out of his backpack. Tapping into the Power Ring's power, Sonic is able to run of the portal's reach. Once in the safe zone, Sonic believes that this was a trap set for him by Dr. Robotnik. Immediately after, Sonic spots a mysterious golden object lying on the ground that he picks up before running back to Knothole Village. Meanwhile, on the other side of the portal, within the Void, the sorcerer Naugus is observing Sonic's surprising speed and Sally's high intellect on a reflective crystal surface.

After returning to Knothole, Sonic meets up with Sally and Bunnie. At the time, Sally is using Nicole to study the Mandaras - an legendary race of giants. After arriving, Sonic tells Sally about his adventure in the Great Unknown before showing her the golden artifact he found. Upon seeing it, Sally is delighted. Seeing that it is associated with the Mandaras, Sally explains that this object is the first proof of their existence. In gratitude, Sally kisses Sonic. Immediately afterward, Dove arrives with a message from Uncle Chuck, which Bunnie reads. When Sonic asks what it says, Bunnie reads that Robotnik is planning something big and that Sonic must come to Robotropolis. Upon hearing this, Sonic runs off to check out what his happening. Sally, on the other hand, decides to investigate the artifact, but when she tries to translate the inscription on the artifact with Nicole, Nicole replies that there is a high probability that the artifact is falsified, as the letters on the artifact do not fit into any historical eras. After explaining what Nicole said in simpler terms to Bunnie, Sally has Nicole display the artifact's letters via a hologram, which Sally begins to analyze individually. Suddenly, however, the artifact flies out of Sally's hands and surround both her and Bunnie in a red aura that seemingly paralyzes them. The girls are then carried out of Knothole by the red energy.

Meanwhile, Sonic has snuck into Chuck's hideout in Robotropolis, which has Hover Units patrolling outside it. Inside the hideout, Chuck replays a recording from Dr. Robotnik, who tells Snively to study the Doomsday Project information he has send him and that he has to have the analysis ready for their next command meeting. Chuck then adds that all of Robotnik's commanders are involved with this "Doomsday Project". Not liking the sound of Robotnik's new plan, Sonic asks Chuck where and when the next command meeting will take place. After searching the data on his computer, Chuck informs Sonic that it has not been determined yet, but he will try to get that piece of information later. However, right now, he has to return to his job before he is missed. After taking a look through his hideout's periscope and ensuring that the coast is clear, Chuck tells Sonic to be careful. Sonic wishes as well good luck to his uncle before taking off. In the meantime, Snively has detected signals coming from the Great Unknown and guesses to himself that Naugus has finally done it. He also takes great interest in how this will play out, before uttering a small chuckle. Snively proceeds to inform Robotnik about the Void activity in the Great Unknown. Surprised by this fact, Robotnik cannot believe this. After walking up to Snively's monitor to see the readings for himself, the worried Robotnik begins recalling past events...

Over eleven years ago, Robotnik and Snively were helping Naugus prepare for a journey into the Void. The sorcerer tells Robotnik to get him out of the Void after an hour. He also warns Robotnik that if he should get any ideas, he would use his magic on him. As a demonstration, Naugus turns Robotnik's head into that of a crow's, making Snively laugh. Robotnik, however, assures Naugus that he has no ill intentions to speak of. Naugus thus disenchants the doctor. In return, Robotnik wishes Naugus a safe journey before activating the Void portal. After Naugus is pulled into the Void however, Robotnik orders Snively to close the portal and turn off all return methods. Although surprised, Snively complies. Robotnik then tells himself that Naugus should not have trusted anyone, especially him.

Back in the present, Snively reminds Robotnik that Naugus is going to be very furious if he gets out of the Void. Initially, Robotnik dismisses the notion, certain that though Naugus can open a portal into the Void, he cannot get out. Snively convinces him, however, to keep a close eye on the Void. Meanwhile, Sonic returns to Knothole, only to disccover that no one is here to welcome him. When he later enters Sally's hut, he finds Nicole lying on the floor. Knowing that Sally never goes anywhere without Nicole, Sonic picks her up and wonders where Sally can be. Meanwhile, Sally and Bunnie have been dragged into the Great Unknown. There, they are pulled into the portal leading into the Void.

Back in Knothole, Sonic is interrogating Nicole, who tells him (in a way that Sonic does not understand) that Sally is not present and that she did not input the place that she went to. Getting frustrated and impatient, Sonic begins to shake Nicole, telling her to tell him what happened before Sally left. Nicole warns Sonic not to shake her violently, because it might damage her circuitry. Sonic, however, does not understand and tells her to "talk in English". Eventually, Sonic stops when Nicole simply tells him to stop shaking her. Nicole then reveals that she can display what happened to Sally and Bunnie before they departed. After Nicole has shown a holographic video of what happened to Sally and Bunnie, Sonic notices the red energy surrounding Sally and Bunnie and asks Nicole about it. Nicole tries to give a scientific explanation, but Sonic has her dumb it down for him, making Nicole state simply that the energy is probably from the Void. Sonic thus decides to head to the Great Unknown and find the Void. Taking Nicole with him, Nicole says in Sonic's manner of speaking that they are taking off. Meanwhile, Naugus has Sally and Bunnie suspended in front of him in a trace. Using his magic, he turns one of the crystals nearby into a chair on which to sit. He then snaps his fingers, releasing Sally and Bunnie. He begins to ask them where Sonic is, but he quickly gets impatient and treats the girls to his spell again. Mesmerized, Sally begins telling Naugus about who Sonic is. Not caring about that, Naugus is more interested in knowing about how Sonic escaped his spell. The mesmerized Sally proceeds to explain that Sonic had already left for Robotropolis when the spell went off. Satisfied, Naugus removes his spell. Wanting answers, Sally asks Naugus about who he is. Naugus proceeds to introduce himself and reveals that the Void (or "Sanctuary" as he calls it) is a discovery of his that Robotnik helped him enter with a portal of the doctor's own design. He proceeds to explain that in the Void, his magic can do anything, except allowing him to escape the Void. As he unveils a portal out of the Void, Naugus reveals that he needs Sonic's speed to escape. He knows though that Sonic will soon show up because he has to save his princess. Naugus then uses his magic to encage Sally and Bunnie in crystals.

Having arrived in the Great Unknown, Sonic runs across the fields while wearing goggles. Unable to find the Void portal, Sonic pulls out Nicole and tells her to find it. Nicole thus begins searching for signals while explaining where to go in a scientific way. Not understanding what Nicole just said, Sonic threatens her with another snaking until she tells him where to go in a simpler way. After Sonic takes off however, Robotnik arrives on the scene in his Command Ship with his Hover Units and army as backup. Snively informs Robotnik that they are within reach, and Robotnik orders Snively to release the Surveillance Orbs, several of which begin to follow Sonic. Meanwhile, Sonic finds himself at the edge of a ravine and pulls out Nicole, who begins to detect various radiant forces. With Sonic telling her to repeat that in a normal language, a somewhat nervous Nicole replies that she is receiving signals from all over the place that are messing her up. She also explains that several of those signals are emitted from Robotnik's machines. Satisfied with Nicole's explanation, Sonic takes off again. Unbeknownst to Sonic, however, Robotnik is observing him through one of his Surveillance Orbs. Wondering what Sonic could be doing so far from home in the middle of nowhere, Robotnik suddenly realizes that Sonic could cooperating with Naugus, prompting him to order all his units to hunt the hedgehog. Not long after, Sonic find himself attacked by Hover Units, which begin firing lasers at him. Finding himself cornered, Sonic asks Nicole for ideas. In return, Nicole proposes using the Super Spin, which Sonic likes. Using the Super Spin, Sonic burrows underground, thus avoiding the lasers. However, Snively informs a frustrated Robotnik that Sonic's movements are being tracked. Snively then gives the predicted exit point that Sonic would emerge from. When Snively switches to the visual of that place, Robotnik sees that it is in the location of the Void portal. Robotnik thus orders his entire fleet to head to that location in order to force Sonic into the portal. After Sonic emerges from the ground, he finds himself getting pulled in from behind by the portal to the Void. To make matters worse, his way forward is blocked by Hover Units firing lasers at him. At the same time, Robotnik is watching Sonic's efforts to escape the pull of the Void portal. Eventually, he orders his Hover Units to sweep the laser fire forward in order to force Sonic closer to the portal.

As Sonic finds himself caught between a rock and a hard place, Nicole instructs Sonic to relax as it was his plan to head into the Void anyway. Listening to Nicole, Sonic assumes a relaxed pose and lets the portal suck him into the Void. Robotnik then begins to celebrate his victory, believing that Sonic has finally been eliminated. He then orders Snively to close the portal to the Void. Snively does as instructed, but encounters resistance. Soon after, the diminished energy from the portal begins to rise again. As such, Robotnik orders everyone to wait and watch the portal, and destroy anyone who tries to escape. Meanwhile, Sonic is flying through the portal and eventually enters the Void. There, he falls into a crystal tunnel that leads him to Naugus, and lands before his feet. Naugus proceeds to greet Sonic, who quickly notices the crystalized Sally and Bunnie. Naugus assures a concerned Sonic that they are fine however, before removing the crystals encasing them. Sally and Bunnie proceed to hug Sonic, and Naugus reveals that he needs his services to escape the Void. While Sonic informs Naugus that Robotnik has already closed the portal, Naugus reveals that it is not a problem as he begins to open the portal again with his magic, revealing that he has spent years studying the Void and how to open the portal, and now even Robotnik's machines cannot stop him. With the portal open, Sally informs Sonic that his speed is the only way to get through the portal. Sonic thus grabs Sally and Bunnie and begins running towards the portal, passing Naugus in the process. Impressed by Sonic's speed, Naugus traps the heroes inside a crystal tunnel by putting up crystal walls in front and behind them. Sonic, however, uses his Super Spin to dig through one of the walls in the tunnel. As the heroes gather in front of the hole Sonic made, they get a view of a beautiful crystal palace on the other side of the hole.

Entering the crystal palace, Sally remarks that it looks much like her father's castle. As Sonic and co. take a look inside one of the rooms, they find the King lying in a bed. Sally immediately runs over to her father, who appears very sick and weak, and she hears from him that he needs her help. He calls upon Sonic, who quickly runs up to him and bows to him. The King subsequently asks Sonic to release him from the Void, saying that he can fix everything. He also promises that he will explain everything once he is outside the Void. While Sonic takes up the mission without hesitation, he wonders how they are going to get past Naugus. It is then that the King explains that Naugus has created everything around them with his magic, and that it is an illusion. As such, they can leave the Void from anywhere if Sonic's uses his speed. Sonic thus starts carrying the King on his back, and Sally tells him to hurry. Sonic proceeds to run through a nearby window, which turns into the portal out of the Void, with the King. Afterward though, Bunnie has a strange feeling that something is not right. Immediately after, Ari appears, whose presence surprises both Sally and Bunnie. Ari proceeds to explain that they have all been fooled: Naugus took the form of the King in order to get help from Sonic, whom he knew would never willingly help him. Ari then moves out of the way, allowing Sally to see the real King. Knowing this is her real father, Sally throws herself into his arms, crying.

Meanwhile, Sonic is running out of the portal on the other side with the false King, avoiding shells from Robotnik's machines in the process. Snively informs Robotnik of Sonic and the supposed "King's" escape from the Void, and Robotnik in turn orders the Void to be closed. After Sonic takes cover behind some rocks though, Naugus sheds his disguise. Not liking the trick Naugus pulled, Sonic confronts the sorcerer. However, before he can do anything, Naugus crystalizes Sonic's body from the neck down. Naugus then tells Sonic to be grateful to him, because he plans to get rid of Robotnik. When a Surveillance Orb then approaches the duo, Sonic explains to Naugus that Robotnik can see them through it. Naugus, with a sinister smile, thus asks Robotnik over the Surveillance Orb if he wants to "play". The terrified Robotnik subsequently turns off his monitor and tries to flee. Meanwhile, Naugus releases Sonic and instructs him to go save his friends. Sonic thus sets off and renters the portal to the Void while Naugus catches Robotnik just as he is getting off his Command Ship. The terrified doctor thus falls on his knees and assures Naugus that he did not betray him. However, Naugus is not buying Robotnik's story and proceeds to turn his head into that of a slug's, followed by a monkey's, a crow's, and finally a pig's. Seeing this, Snively begins to weep from laugher until he falls down from his chair.

Inside the Void, Sally is wondering where Sonic is. Just as Bunnie assures her that Sonic will be there, Sonic arrives and proclaims that he is taking everyone out of the Void. Meanwhile, Naugus is still toying with Robotnik, but before he can cast another spell, he notices that his legs are beginning to crystalize. The sorcerer thus decides to change Robotnik back to normal before telling him that they are going to play hide-and-seek now. Naugus thus turns around, closes his eyes and starts counting to ten. Robtonik desperately tries to convince Naugus that he did not betray him, but when that fails, he decides to flee to his Command Ship and have Snively fly them away. After the doctor and his forces have left, Naugus finishes counting down, just as Sonic and his friends arrive. Sonic does not like the fact that Robotnik is getting away, but Naugus insists that it could not be helped. As it turns out, Naugus has misunderstood the properties of the Void. Due to having resided in the Void for so long, existing outside of it now causes him to crystalize and lose his life force. Only by returning to the Void can he save his own life, as it is only within that dimension that he can control the crystallization process. To make matters worse for the heroes, the same thing is happening to the King as well, meaning that he has to go back to the Void as well. Comforting a sadden Sally about how things have turned out, the King tells Sally to look into his pocket. There, she finds a device that holds a list of all the Freedom Fighter groups. Sally, however, can only cry because she thought she had finally saved her father. The King and Sally then say their goodbyes before Sonic grabs Sally and takes off, although not before wishing the King good luck. Naugus then proceeds to open the portal to the Void again, and lets himself and the King get pulled into the Void once more. Naugus promises Robotnik, however, that he will return and have his revenge. As the portal closes, Sonic hugs a crying Sally.

Later, at the Lake of Rings, Sally is still sad. Sonic comforts her, however, by saying that she at least got to see her father again and that Naugus would find a way to get them out of the Void. Additionally, they managed to get a list of the Freedom Fighter groups and Ari. Feeling better, Sally agrees with Sonic, and begins to walk with him. During the walk, Sonic and Sally begin teasing each other. Meanwhile, Nicole takes Sonic's side in their argument ("He's cool, Sal. Way past."), leaving Sally to wonder just what Sonic has done to her.